This invention relates to molded case circuit breakers and more particularly to a solid state molded case circuit breaker which has control terminals.
Circuit breakers are designed to interrupt the flow of electric current in a circuit under certain preselected conditions. For example, the circuit breaker may open the circuit if the current magnitude becomes too high, the voltage becomes too low or one phase of a multi-phase circuit carries more current than another phase of the circuit. In addition to these functions, the circuit breaker may be called upon to perform other functions which it must be wired to accomplish. These functions can be accomplished by the use of control wiring which attaches to the control terminals on the circuit breaker. Thus, the circuit breaker control terminals might include terminals for receiving 120 volt AC control voltage. The terminals might also include test terminals which can be operated to test the operation of the breaker. The terminals may also provide for connection to an external transformer for ground fault sensing or may have terminals available which perform switching functions under certain conditions for sounding alarms or other auxiliary functions. Thus, it can be appreciated that the control functions of the circuit breaker are indeed important and useful functions which are facilitated by the use of control terminals.
Typically, circuit breakers have provided the control terminals either on the rear of the molded casing or on the side of the molded casing. When the control terminals are located on the rear of the circuit breaker casing, the installed circuit breaker has to be removed before a connection can be established or a change can be made in the control circuits. This requires removing the circuit breaker from the panel and disconnecting power to the breaker.
Similarly, when the control terminals are located on the side of the circuit breaker housing and the circuit breaker is installed in a control panel as is typical, the terminals are inaccessible. To change the wiring, the breaker must be removed from the panelboard, which entails interrupting power at least from the circuit breaker. While the wiring is being checked or changed, the circuit breaker is out of service, which may cause equipment down time in an industrial or manufacturing operation. Since downtime of equipment ordinarily idles many workers, downtime is quite expensive and is an item which must be minimized. Accordingly, it will be appreciated that it will be highly desirable to provide a circuit breaker which has terminals which are accessible for adding or changing wiring without having to remove the circuit breaker from the panel while the changes are made.
Accordingly, it is an object of the present invention to provide a molded case circuit breaker which has control terminals.
Another object of the present invention is to provide a molded case circuit breaker which has terminals which are easily accessible.
Another object of the present invention is to provide terminals which are easily accessible for inspection without removing the circuit breaker from the panelboard.